WO2018024974A1 - Device for calibrating microphones - Google Patents

Device for calibrating microphones Download PDF

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Publication number
WO2018024974A1
WO2018024974A1 PCT/FR2017/052148 FR2017052148W WO2018024974A1 WO 2018024974 A1 WO2018024974 A1 WO 2018024974A1 FR 2017052148 W FR2017052148 W FR 2017052148W WO 2018024974 A1 WO2018024974 A1 WO 2018024974A1
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WO
WIPO (PCT)
Prior art keywords
microphone
microphones
sound
processing device
digital audio
Prior art date
Application number
PCT/FR2017/052148
Other languages
French (fr)
Inventor
Jacques Delacoux
Original Assignee
Aaton Digital
Sas Ithaki
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to FR1657451 priority Critical
Priority to FR1657451A priority patent/FR3054769B1/en
Application filed by Aaton Digital, Sas Ithaki filed Critical Aaton Digital
Publication of WO2018024974A1 publication Critical patent/WO2018024974A1/en

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00Circuits for transducers, loudspeakers or microphones
    • H04R3/04Circuits for transducers, loudspeakers or microphones for correcting frequency response
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R29/00Monitoring arrangements; Testing arrangements
    • H04R29/001Monitoring arrangements; Testing arrangements for loudspeakers
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R29/00Monitoring arrangements; Testing arrangements
    • H04R29/004Monitoring arrangements; Testing arrangements for microphones
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00Circuits for transducers, loudspeakers or microphones
    • H04R3/005Circuits for transducers, loudspeakers or microphones for combining the signals of two or more microphones
    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04RLOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2201/00Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
    • H04R2201/02Details casings, cabinets or mounting therein for transducers covered by H04R1/02 but not provided for in any of its subgroups
    • H04R2201/028Structural combinations of loudspeakers with built-in power amplifiers, e.g. in the same acoustic enclosure

Abstract

The invention relates to a calibration device (30) comprising a sound pick-up system (31) comprising microphones (40) connected to an audio signal processing device (34), the calibration device further comprising an enclosure (32) at least partially containing the processing device, a sound generator (36) connected to the processing device, and a microphone support (44) capable of keeping the microphones at the same distance from the sound generator.

Description

 DEVICE FOR CALIBRATING MICROPHONES

The present patent application claims the priority of the French patent application FRl 6/57451 which will be considered as an integral part of the present description.

Field

 The present application relates to a device and method for calibrating microphones in an electronic system, including a sound pickup system.

Presentation of the prior art

 Some electronic systems, including sound recording systems, may include a plurality of microphones, particularly for improving the quality of the recorded acoustic information and / or extracting information about sound sources and / or surroundings.

FIG. 1 represents, partly and schematically, an exemplary sound pickup system 10 comprising a plurality of microphones 12 which are distributed over the site 14 on which sound recording is performed. The microphones 12 are connected to an audio signal processing device 16. The microphones 12 transmit to the processing device 16 analog or digital electrical signals resulting from the conversion of the sound waves, and the processing device 16 applies a processing to the audio signals digital from signals provided by the microphones, and for example produces and stores digital audio files.

 When processing the signals provided by the microphones 12, the processing device 16 generally operates by default as if the properties of the microphones 12 were identical. An example of a property is the time that elapses between the moment of reception of a sound wave by the microphone 12 and the moment at which the processing device 16 begins to perform a processing on the digital audio signal obtained by analog conversion / digital signal picked up by the microphone 12. This delay is called transmission delay thereafter. Other examples of microphone properties are phase shift and gain when converting the sound signal.

However, the properties of the microphones 12 are generally not identical. For example, the transmission delays associated with the microphones are generally not identical and must be taken into account when generating the audio files by the processing device 16, so that, when these audio files are listened to, a suitable sound reproduction is obtained. Transmission delays differ especially between analog microphones and digital microphones. An analog microphone transmits to the processing device an analog signal representative of the sound waves received by the microphone and the processing device performs the analog / digital conversion of this analog signal. An analog microphone is generally connected to the processing device by a wired link so that the duration of the analog signal transfer from the analog microphone to the processing device is negligible. A digital microphone includes a digital-to-analog converter that converts the analog signal from the conversion of the sound signal into a digital signal transmitted to the processing device. In addition, the transmission of the digital or analog microphone signals to the processing device 16 may be a wireless transmission using electromagnetic waves. The transmission delay of the microphone then includes, in addition, the delay for the transmission and reception of electromagnetic waves but also the delay for possible encoding and error correction processing by the transmitter. FIG. 1 schematically shows four microphones 12 including three microphones 12 connected to the processing device 16 by a wire link 18 and a microphone 12 connected to the processing device 16 by a wireless link 20.

 For some applications, it may be necessary to provide a calibration step of the sound pickup system 10 to determine the differences between the properties of the microphones 12 and possibly determine means for compensating for these differences. By way of example, the compensation of the differences between the transmission delays of the microphones 12 may include the addition by an operator of variable delays, stored by the processing device 16, so that the start times of recording of the audio files are identical. By way of example, the compensation of the differences between the amplification ratios and the phase offsets of the microphones 12 may include the addition of a filter applied by the processing device 16 to the signals supplied by the microphones 12 so that the Recorded audio files correspond to the audio files that would be obtained if the amplification ratios and phase shifts of the microphones 12 were identical.

An exemplary calibration method of the sound pickup system 10 comprises the emission by a sound generator 24, for example a loudspeaker, possibly controlled by the processing device 16, of several known sequences of sound signals and the analyzing the audio files provided by the processing device 16 following the acquisition of these sound signal sequences by the microphones 12. There is a delay of propagation of each sound signal from the speaker 24 to each microphone 12. This delay may vary from one microphone to another depending on the relative position between the microphone 12 and the speaker 24. A disadvantage is that it can then be difficult from the analysis of the audio files to separate, for each microphone 12, the transmission delay associated with the microphone 12 of the propagation delay.

 It may then be difficult to automatically adapt the compensation means determined during the calibration to a new arrangement of the microphones, and an operator must generally perform a manual adaptation of the compensation means to each new arrangement of the microphones, which is a long and tedious operation. summary

 An object of an embodiment is to provide a calibration device of a sound pickup system that overcomes all or part of the disadvantages of the devices described above.

 Another object of an embodiment is that the calibration can be performed automatically.

 Another object of an embodiment is that the calibration can be performed in a simple manner.

 Another object of an embodiment is that the calibration can be performed quickly.

 Thus, an embodiment provides a calibration device comprising a sound pickup system comprising microphones connected to an audio signal processing device, the calibration device further comprising an enclosure containing at least a portion of the processing device, a sound generator connected to the processing device, and a microphone holder adapted to hold the microphones at the same distance from the sound generator.

According to one embodiment, the device further comprises an accumulator battery. According to one embodiment, the sound generator is located between the support and the processing device.

 According to one embodiment, the sound generator is in contact with the support.

 According to one embodiment, the support is at least partly made of an elastic material.

 According to one embodiment, the support comprises holes receiving the microphones, and at least one of the holes has a shape at least partially complementary to one of the microphones.

 According to one embodiment, the minimum distance separating each microphone from the sound generator is less than 20 cm.

 According to one embodiment, the number of microphones is greater than or equal to five.

 One embodiment also provides for the use of the calibration device as previously defined for the calibration of the microphones of the sound recording system.

 According to one embodiment, the use comprises the following steps:

 transmitting at least one sound signal by the sound generator;

 capturing the sound signal by each microphone and, for each microphone, acquiring a digital audio signal from the processing device; and

 analyzing digital audio signals to determine, for each microphone, at least one of the transmission delay, the phase shift and the microphone conversion gain.

According to one embodiment, the use further comprises the step of adding, for at least one of the microphones, a delay by the processing device during subsequent acquisitions of digital audio signals representative of sound signals picked up by said microphone. Brief description of the drawings

 These and other features and advantages will be set forth in detail in the following description of particular embodiments in a non-limiting manner with reference to the accompanying drawings in which:

 Figure 1, described above, partially and schematically shows an example of sound recording system;

 Figures 2 and 3 are sectional views, partial and schematic, of an embodiment of a calibration device of a sound recording system;

 Figure 4 is a partial sectional and schematic, similar to Figure 3 of another embodiment of a calibration device of a sound recording system;

 Fig. 5 is a block diagram of one embodiment of a method of calibrating a sound recording system;

 FIG. 6 represents an exemplary envelope of an audio signal emitted by a loudspeaker and the digital audio signals acquired by a processing device of the calibration device of FIG. 2 during the implementation of the method of FIG. calibration illustrated in Figure 5; and

 Fig. 7 is a block diagram of a more detailed embodiment of a step of the calibration method illustrated in Fig. 5.

detailed description

 The same elements have been designated with the same references in the various figures. For the sake of clarity, only the elements that are useful for understanding the described embodiments have been shown and are detailed. In particular, microphone structures and a device for processing sounds picked up by microphones are well known and are not described in detail later.

In the description which follows, when reference is made to absolute position qualifiers, such as the terms "before", "backward", "up", "down", "left", "right", etc., or relative, such as the terms "above", "below", "upper", "lower", etc., or with qualifiers for orientation, such as the terms "horizontal", "vertical", etc. ., reference is made to the orientation of the figures or to a sound recording system in a normal position of use. Unless otherwise specified, the terms "approximately", "substantially", and "of the order of" mean within 10%, preferably within 5%.

 According to one embodiment, for the calibration of microphones, it is intended to arrange the microphones near a loudspeaker in a fixed and known configuration. The relative position between each microphone and the speaker is then known beforehand. Preferably, the microphones are arranged so that the propagation delay of the sound waves from the loudspeaker to each microphone is substantially constant. Determining the transmission delays of the microphones is then facilitated. In the remainder of the description, the terms "sound signal" and "acoustic signal" are used interchangeably.

 FIGS. 2 and 3 are sectional, partial and schematic views of an embodiment of a calibration device 30 of a sound recording system 31.

 The calibration device 30 comprises an enclosure 32 in which the elements of the sound recording system 31 are arranged, in particular a device for processing sound signals.

34. The chamber 32 further contains a sound generator 36, for example a loudspeaker, preferably connected to the processing device 34 and controlled by the processing device 34. The loudspeaker 36 can be connected to the device treatment 34 by a wired link or be controlled by the processing device 34 by a wireless link, including implementing electromagnetic waves. The loudspeaker 36 is preferably located above the processing device 34. The processing device 34 corresponds, for example, to the product marketed by Aaton-Digital under the name Cantar-X3. The processing device 34 may comprise a dedicated electronic circuit and / or a processor, for example a microcontroller, adapted to execute the instructions of a computer program stored in a memory. The speaker 36 may be a broadband speaker. An electric storage battery 38 for the power supply of the treatment device 34 and / or the speaker 36 may be disposed in the enclosure 32. The battery 38 may be located between the treatment device 34 and the loudspeaker 34. Alternatively, the processor 34 may be located between the loudspeaker 36 and the battery 38.

 According to one embodiment, the loudspeaker 36 and / or the electric storage battery 38 may be integrated wholly or partly into the processing device 34.

 The pick-up system 31 further includes microphones 40 connected to the processing device 34. The number of microphones 40 may be between 2 and 50, preferably between 2 and 20. For example, on the microphones 40 Figures 2 and 3, there is shown a processing device 34 connected to five microphones 40. Each microphone 40 may be connected to the processing device 34 by a wire link or a wireless link implementing the transmission of electromagnetic waves. By way of example, in FIG. 2, there are shown five microphones 40 including two microphones each of which is connected to the processing device 34 by a cable 42 and a microphone transmits signals to the processing device 34 via a wireless link, no represented.

Each microphone 40 comprises a transducer adapted to receive an acoustic signal S (t) and to convert it into an analog electrical signal S e (t), also called analog audio signal, where t indicates a time variable. Each microphone 40 has a transfer function H which, in the frequency domain, is given by the following relation (1):

Η (ω) = Α (ω) εχρ (ίΦ (ω)) (1) where ω is the pulsation of the acoustic signal, A is the conversion gain that can depend on the frequency and Φ and the phase shift that can depend on the frequency.

The processing device 34 is adapted to determine, for each microphone 40, a digital audio signal S n from the analog audio signal S e (t). The microphone 40 can transmit the analog audio signal S e (t) to the processing device 34 which then converts the analog audio signal to obtain the digital audio signal S n . Alternatively, the microphone 40 can perform the analog-to-digital conversion of the analog audio signal S e (t) and directly supply the digital audio signal S n to the processing device 34. For each microphone 40, the processing device 34 is adapted to perform a processing on the digital audio signal S n to provide a digital audio file. The processing may comprise the conditioning of the digital audio signal S n , for example the application of a filter to the digital audio signal, the mixing of the digital audio signal with another digital audio signal and / or the recording of the digital audio file comprising the digital audio signal S n and possibly additional data. The transmission delay of the microphone 40 corresponds to the delay between the moment when the microphone begins to receive the sound signal S (t) and the moment when the processing device 34 starts the processing applied to the digital audio signal, for example the moment where the processing device 34 starts the conditioning of the digital audio signal S n , the moment when the processing device 34 starts mixing the digital audio signal S n with another digital audio signal or the moment when the processing device 34 starts to storing the digital audio file representative of the sound signal S (t).

The calibration device 30 further comprises a support 44 disposed at least partially in the enclosure 32 and comprising holes 46 in which the microphones 40 are arranged in part. Preferably, the support 40 is in contact with the loudspeaker 40. 36. According to one embodiment, the support 44 comprises an elastic material at least at each hole 46 so that the support 44 can slightly deform upon insertion of the microphone 40 into the hole 46. The support 44 is, for example, at least partly foam. According to one embodiment, each hole 46 has a shape complementary to a part of a microphone 40 so that, when a microphone 40 is disposed in a hole 46, the microphone 40 remains substantially immobile with respect to the speaker 32, for example by the friction exerted by the support 44 on the microphone 40. The holes 46 present in the support 44 may be identical. Alternatively, the holes 46 may have different shapes in the case where microphones of different shapes are used. In Figure 3, the holes 46 are shown in an aligned fashion.

 According to one embodiment, the enclosure 32 may be a single piece or comprise several pieces connected to each other. According to one embodiment, the enclosure 32 may comprise a frame whose internal wall has a shape complementary to the various elements housed in the enclosure 32. As an alternative, shims may, in addition, be arranged in the enclosure 32, between the enclosure 32 and the processing device 34, the battery 38, the loudspeaker 36 and / or the support 44 to facilitate the holding in position of these elements in the enclosure 32. By way of example, the enclosure 32 is made of plastic material.

 Figure 4 is a view similar to Figure 3 of another embodiment of the support 44 in which the holes 46 are arranged at the corners of a regular polygon. Alternatively, the holes 46 may be divided into rows and columns.

According to another embodiment, the support 44 may comprise a plurality of microphone clamps, preferably connected by a frame rigid to each other, each microphone 40 being held by one of the clamps when using the calibration device 30. When the microphones 40 are placed on the support 44, the capsules of the microphones 40 are preferably placed relative to the speaker 36 so that the sound waves emitted by the loudspeaker are substantially flat when they reach the microphones. 40 and at the same time reach the capsules of the microphones 40. According to one embodiment, the capsules of the microphones 40 are disposed equidistant from the loudspeaker 36.

 According to one embodiment, the distance between the capsule of each microphone 40 and the speaker 36 is between 2 cm and 20 cm, preferably between 2 cm and 10 cm.

 FIG. 5 represents an embodiment of a method of calibrating the sound recording system 31.

 Step 50 corresponds to the mounting of the calibration device 30 which comprises the stack, in the chamber 32, of the processing device 34, the battery 38, the loudspeaker 36, and the support 44. The enclosure 32 holds the processor device 34, the battery 38, the speaker 36 and the support 44 in position. The speaker 32 ensures that the microphones 40 remain motionless relative to the loudspeaker 36 during the calibration operation. The process continues in step 52.

 In step 52, sound signals are emitted by the loudspeaker 36. These sound signals are picked up by the microphones 40. Each sound signal may correspond to a pure sound emitted during a determined transmission duration, that is, ie to a sound signal at a single frequency. The frequency of the pure sound can be constant during the duration of emission or vary during the duration of emission. By way of example, the frequency of the pure sound can increase or decrease with a constant rate of change during the transmission duration, which corresponds to a frequency ramp.

The process continues in step 54.

In step 54, for each microphone 40, a digital audio signal S n is acquired by the processing device 34 from the sound signal picked up by the microphone in step 52, the digital audio signal S n being received or determined by the processing device 34. As previously described, the processing device can perform various processing on digital audio signals Sn, including providing and storing audio files.

 Steps 52 and 54 are repeated for each sound signal provided by loudspeaker 36. The process proceeds to step 56.

FIG. 6 schematically shows an exemplary envelope S¾ of the control signal of loudspeaker 36 for the transmission of a sound signal and the digital audio signals S n] _ and S n 2 acquired by the processing device. 34 from the sound signals that are picked up by two microphones 40 during the transmission of the sound signal by the speaker 36. The envelope Su comprises, for example, successively a rising edge Attack, a steady level zone Sustain, and a falling edge. However, other forms of envelope S¾ can be used. The instant t ] _ corresponds to the instant of detection of the rising edge of the signal S n] _ and the instant t2 corresponds to the instant of detection of the rising edge of the signal S n 2 · We call At the delay of the moment t2 with respect to time t ] _.

Referring again to FIG. 5, at step 56, characteristics of the microphones 40 are determined by the processor 34 from the analysis of the digital audio signals S n provided in step 54. The characteristics can be the transmission delay, the phase shift and / or the amplification ratio of each microphone 40. Advantageously, since the shape of the support 44 is known in advance, the relative positions between the microphones 40 placed in the holes 46 and the speaker 36 are known in advance. The propagation delay of each sound signal from the loudspeaker 36 to each microphone 40 is therefore known beforehand. Furthermore, preferably, the configuration of the microphones 40 is defined so that the propagation delays of each sound signal emitted by the loudspeaker 36 to the microphones 40 are substantially identical. An exemplary method for analyzing digital audio signals is described in patent application FR 2764088. The analysis method may include comparing the digital audio signals with each other. By way of example, for each sound signal emitted by the loudspeaker 36 and for each pair of microphones comprising a first microphone and a second microphone, the analysis method may comprise the determination of the delay At between the instant t] the beginning of the first digital audio signal S n ] _ with respect to the start time -2 of the second digital audio signal S n 2 as acquired by the processing device 34. By way of example, the instant The beginning of a digital audio signal may correspond to the instant at which the digital audio signal exceeds a threshold. In another example, the digital audio signal is compared to a template by temporally moving the template relative to the digital audio signal until a criterion is met, for example the maximum overlap of the digital audio signal by the template. The start time of the digital audio signal is then obtained from the determined position of the template.

 Alternatively, rather than processing applied to the two digital audio signals associated with a pair of microphones 40, simultaneous processing of more than two digital audio signals associated with more than two microphones 40 may be realized.

In step 58, the processing device 34 can modify some of its operating parameters according to the results obtained in step 56. According to one embodiment, the processing device 34 is adapted to modify, for each microphone 40 , the delay between the actual start of the digital audio signal acquired by the processing device 34 and corresponding to an audio signal picked up by the microphone 40 and the beginning of the processing applied by the processing device 34 to the digital audio signal. This delay is called the wait time afterwards. As a variant, the treatment device can shift the start time of the digital audio signal by a time equal to the waiting time.

 According to one embodiment, the processing device 34 automatically modifies the delay times associated with the microphones so that processing of the digital audio signals by the processing device starts simultaneously, as if the start times of the digital audio signals were identical. According to one embodiment, in step 56, the processing device 34 determines for which microphone 40 the delay At is the highest and, in step 58, the waiting times associated with the other microphones are then modified to that the start time of each digital audio signal corresponds to the start time of the digital audio signal having the highest delay.

 Regardless of what has been described above, the processing performed by the processing device 34 may include the introduction of an additional delay for certain digital audio signals, in particular by delaying the start of the recording of digital audio files, for example to achieve a desired sound effect (creating an echo, obtaining an impression of distance, etc.).

 In step 60, the processing device 34 determines whether the digital audio signals satisfy certain criteria. If the digital audio signals do not meet the criteria, the method returns to step 52 and a new calibration operation is performed. For example, digital audio signals can be compared to templates. If the digital audio signals satisfy the criteria, the process proceeds to step 62.

In step 62, the processing device 34 determines the phase shift between the digital audio signals acquired by the processing device 34 from the sound signals picked up by the microphones 40. The step 62 may not be present. In step 64, the processor 34 may indicate to an operator that the calibration operation is complete. For example, it can be provided the display of information on a display screen indicating the delay associated with each microphone 40.

 Fig. 7 shows a more detailed embodiment of a method for determining the phases of the audio signals at step 62 previously described.

 In step 70, sound signals are emitted by the loudspeaker 36. These sound signals are picked up by the microphones 40. Each sound signal corresponds to a pure sound emitted during a determined transmission duration, that is to say Saying a sound signal at a single frequency. The frequency of the pure sound can be constant during the duration of emission or vary during the duration of emission. By way of example, the frequency of the pure sound can increase or decrease with a constant rate of change during the transmission duration, which corresponds to a frequency ramp.

 In step 72, for each sound signal and for each pair of microphones comprising a first microphone and a second microphone, the processing device 34 can determine the sum of the first digital audio signal associated with the first microphone and the second associated digital audio signal. at the second microphone to determine the phase shift between the first and second digital audio signals.

In step 74, the processing device 34 can modify the digital audio signals S n to compensate for the phase offsets determined in step 72. According to one embodiment, in step 74, the processing device 34 determines the digital audio signal having a correct phase and digital audio signals that do not have the correct phase are changed. By way of example, the correct phase corresponds to the phase common to the largest number of digital audio signals among all the signals acquired by the processing device 34. Steps 52 to 64 of the microphone calibration 40 of the pick-up system 31 may advantageously be performed quickly and automatically by the recording device 31.

 Particular embodiments have been described.

Various variations and modifications will be apparent to those skilled in the art.

Claims

A calibrating device (30) comprising a sound pickup system (31) comprising microphones (40) connected to an audio signal processing device (34), the calibration device further comprising a loudspeaker (32) at least partially containing the processing device, a sound generator (36) connected to the processing device, and a microphone support (44) adapted to hold the microphones at the same distance from the sound generator, the processing device being adapted to control the emission of at least one sound signal by the sound generator (36), each microphone (40) being adapted to pick up the sound signal, the processing device (34) being adapted, for each microphone, to acquiring a digital audio signal, the processing device being adapted to analyze the digital audio signals to determine, for each microphone, the transmission delay of the microphone, and to add, for at least one of the microphones ones (40), a delay in subsequent acquisitions of digital audio signals representative of sound signals picked up by said microphone.
 2. Device according to claim 1, further comprising an accumulator battery (38).
 3. Device according to claim 1 or 2, wherein the sound generator (36) is located between the support (44) and the treatment device (34).
 4. Device according to any one of claims 1 to 3, wherein the sound generator (36) is in contact with the support (44).
 5. Device according to any one of claims 1 to 4, wherein the support (44) is at least partly made of an elastic material.
 6. Device according to any one of the claims
1 to 5, wherein the support (44) comprises holes receiving the microphones, at least one of the holes (46) having a shape at least partly complementary to one of the microphones (40).
7. Device according to any one of claims 1 to 6, wherein the minimum distance between each microphone (40) of the sound generator (36) is less than 20 cm.
 8. Device according to any one of claims 1 to 6, wherein the number of microphones (40) is greater than or equal to five.
 9. Use of the calibration device (30) according to any one of claims 1 to 8 for calibrating the microphones (40) of the sound recording system (31), comprising the following steps:
 transmitting at least one sound signal by the sound generator (36);
 capturing the sound signal by each microphone (40) and, for each microphone, acquiring a digital audio signal from the processing device (34);
 analyzing digital audio signals to determine, for each microphone, at least one of the transmission delay, the phase shift and the microphone conversion gain;
 adding, for at least one of the microphones (40), a delay by the processing device (34) during subsequent acquisitions of digital audio signals representative of sound signals picked up by said microphone.
 The use of claim 9, further comprising the step of analyzing the digital audio signals to determine, for each microphone, at least one of the phase shift and the microphone conversion gain.
PCT/FR2017/052148 2016-08-01 2017-07-31 Device for calibrating microphones WO2018024974A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
FR1657451 2016-08-01
FR1657451A FR3054769B1 (en) 2016-08-01 2016-08-01 Calibration device for microphones

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US16/322,797 US20190182591A1 (en) 2016-08-01 2017-07-31 Device for calibrating microphones
EP17757804.4A EP3491842A1 (en) 2016-08-01 2017-07-31 Device for calibrating microphones

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5567863A (en) * 1995-05-15 1996-10-22 Larson-Davis, Inc. Intensity acoustic calibrator
FR2764088A1 (en) 1997-05-28 1998-12-04 Aaton Sa Film sound track synchronisation detector and marker
US20040165735A1 (en) * 2003-02-25 2004-08-26 Akg Acoustics Gmbh Self-calibration of array microphones
US20070223730A1 (en) * 2003-03-25 2007-09-27 Robert Hickling Normalization and calibration of microphones in sound-intensity probes
US20080175407A1 (en) * 2007-01-23 2008-07-24 Fortemedia, Inc. System and method for calibrating phase and gain mismatches of an array microphone

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5567863A (en) * 1995-05-15 1996-10-22 Larson-Davis, Inc. Intensity acoustic calibrator
FR2764088A1 (en) 1997-05-28 1998-12-04 Aaton Sa Film sound track synchronisation detector and marker
US20040165735A1 (en) * 2003-02-25 2004-08-26 Akg Acoustics Gmbh Self-calibration of array microphones
US20070223730A1 (en) * 2003-03-25 2007-09-27 Robert Hickling Normalization and calibration of microphones in sound-intensity probes
US20080175407A1 (en) * 2007-01-23 2008-07-24 Fortemedia, Inc. System and method for calibrating phase and gain mismatches of an array microphone

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FR3054769A1 (en) 2018-02-02
US20190182591A1 (en) 2019-06-13
EP3491842A1 (en) 2019-06-05
FR3054769B1 (en) 2018-08-31

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